This invention relates in general to universal joints, such as are commonly used in vehicular drive train systems. In particular, this invention relates to an improved structure for quickly, inexpensively, and reliably retaining a pair of bearing cups on an opposed pair of trunnions of a journal cross for a universal joint, such as during shipment from one manufacturing location to another.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. Frequently, the source generates rotational power, and such rotational power is transferred from the source to a rotatably driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
Each of the universal joints typically includes a journal cross having a central body portion with four cylindrical trunnions extending outwardly therefrom. The trunnions are oriented in a single plane and extend at right angles relative to one another. A hollow cylindrical bearing cup is mounted on the end of each of the trunnions. Needle bearings or other friction-reducing structures are provided between the outer cylindrical surfaces of the trunnions and the inner cylindrical surfaces of the bearing cups to permit rotational movement of the bearing cups relative to the trunnions during operation of the universal joint. In the front universal joint of the above-described driveshaft assembly, the bearing cups supported on the first opposed pair of the trunnions on a front journal cross are connected to the front end fitting of the driveshaft assembly, while the bearing cups supported on the second opposed pair of the trunnions on the front journal cross are connected to an end fitting secured to the output shaft of the engine/transmission assembly. Similarly, in the rear universal joint of the above-described driveshaft assembly, the bearing cups supported on the first opposed pair of the trunnions on a rear journal cross are connected to the rear end fitting of the driveshaft assembly, while the bearing cups supported on the second opposed pair of the trunnions on the rear journal cross are connected to an end fitting secured to the input shaft of the axle assembly.
Frequently, the driveshaft assembly (including the driveshaft tube, the front and rear end fittings, and the journal crosses for the front and rear universal joints) is assembled at a first manufacturing location, then shipped as a unit to a second manufacturing location for assembly with the other components of the vehicle drive train system. In such an assembly process, the bearing cups supported on the first opposed pairs of the trunnions on both the front and rear journal crosses are connected to the associated front and rear end fittings of the driveshaft assembly. However, the bearing cups supported on the second opposed pairs of the trunnions on the front and rear journal crosses are not positively retained thereon. As a result, these non-retained bearing cups can move apart from one another on the journal crosses, such as when the respective universal joints are purged with lubricant. Also, these non-retained bearing cups can be inadvertently removed from the journal crosses and become lost during shipment from the first manufacturing location to the second manufacturing location.
To address this, a variety of straps are known in the art for positively retaining these bearing cups on their associated journal crosses. However, known retainer straps have been found to be somewhat time-consuming to install and remove. Also, known retainer straps have been found to be relatively expensive. Lastly, in some instances, known retainer straps have been found themselves to become dislodged from the bearing cups during shipment. Accordingly, it would be desirable to provide an improved structure for quickly, inexpensively, and reliably retaining a pair of bearing cups on an opposed pair of trunnions of a journal cross for a universal joint, such as during shipment from one manufacturing location to another.